Here is what I posted in another thread about the new DNT Zulus V2:
I got my Zulus V2 Friday and set it up yesterday. Not sure I'm a fan of the built in memory. I did the firmware update and then received a memory card error (with no way to swap it for a good one) and it wouldn't record. Luckily, I was able to clear it by rebooting the scope and it all seems to be working well now, but what happens if it fails in the future? I like the new menu system, but not sure why they had to flip-flop all the controls on the top of the scope, it makes it confusing when you have a couple Zulus V1's and know where the buttons are and what they do! I haven't compared the video recordings yet, but I don't really notice a big difference with the internal view. I'm not sure it's worth the extra $100 for the V2. Another oddity... The 21700 batteries that come with it are just a tad narrower than the 21700 batteries sold on Amazon. I have ordered two separate sets of 21700 batteries and both sets won't fit in the battery compartment of the Zulus V2. So, if these batteries that came with the V2 die, you may be out of luck ordering replacements from anywhere but DNT! And, if the memory dies or gets corrupt, and it's outside the warranty, it may be an expense to replace it if it has to be sent in to do so. The one positive I found, it does connect to my phone a lot better than the V1, but so far that's the only real improvement I'm seeing... I kind of regret getting the V2, and I wish I had just spent the few dollars more and gotten the V1 LRF model. There’s just something about this presentation of the Zulus. I can‘t seem to put my finger on it… I like the new model, but can't afford it. Maintenance costs are probably overwhelming.
www.airgunnation.com
I have 2 Zulus 520HD V1 scopes, 1 312HD V1, 520HD-LRF V1 and 1 520HD V2. IMHO, the best one is the 520HD-LRF V1. Best bang for the buck is the 520HD V1 @ just over $300!
To address your question about the 520HD over the 312HD, If I were shooting larger prey and longer distances, the 312HD would be great for its greater field of view. But for shooting rats and mice at 50 yards or less (which is primarily what I do), the 520HD is perfect! I rarely use zoom power over 7.5X and the sight view is very crisp and clear. Also, if you choose to record a video of your shot, it will be clearer at the lower magnifications. So, essentially the more you zoom in, the more degraded the view do to pixelation. None of these scopes use optical zoom, only digital zoom, so the higher the zoom power, the lower the resolution. For this reason, shooting a rat at 5 power is going to be way clearer on the 520HD than 5 power on the 312HD scope. I hope this helps.